Rinde, ein Ersatz fuer Torf?

1989

S. 582-584

21 Lit. Ang.

Unselbständiges Werk

200021001

In order to save peat and to use the limited peat resources sparingly led to the search for substitute products is bark. Bark mulch is frequently used by forest nurseries. The growth inhibitors in the bark reduce the growth of weeds and the bark promotes soil development. If bark mulch is tilled into the soil nitrogen has to be added to reduce the C:N ratio from 100:1 to 20- 30:1. The trade name for this product where N has been added is barkhumus or compost. A further bark-compost product to which various products have been added (peat, clay, sand) is called bark-culture-substrate. It is supposed to be a complete planting-medium for all types of container plants - similar to peat-culture-substrates. Investigations and practical experience have been sceptical whether it is a true substitute because of its physical properties and high variation in its mineral contents as well as the relatively high pH. In a pure form the risk of using bark-culture-substrate is too great for container plants. However it can be recommended as a supplement of 25-30 % by volume to the peat culture-substrate. Bark-culture-substrate as well as barkhumus can be added to the peat-culture-substrate in equal amounts. For peat substrates where water logging is a problem, the bark products can improve the physical properties of the substrate and lead to better drainage. Of the 2-3 million m3 of bark which accumulate annually in the Federal Republic of Germany about 550 000 m3 were utilized for the above mentioned products (1981). Only about 20-30 % of the peat used in horticulture (500 000 m3) is used for the production of peat-culture- substrate. Bark is thus a valuable natural resource which can reduce the use of peat, especially in the area of soil improvement and mulching. For the near future however we cannot do entirely without peat-culture-substrate as a potting substrate in horticulture and gardening and as a substrate for forest-container plants. However, the possibilities of using bark products as a substrate additive should be utilized more effectively.